According to one tradition, Mara was born in the province of Lasta, which was his power base. Originally a general of Dil Na'od, whose daughter Masoba Warq became his wife, Mara overthrew his father-in-law to found the new dynasty.[2]James Bruce, on the other hand, presents another tradition that Dil Na'od was overthrown by Gudit, and that Mara Takla Haymanot (whom Bruce calls "Takla Haymanot") was a cousin of Gudit who succeeded her after several of her own family.[3]

There is some disagreement over the exact time when he came to the throne: there are two different traditions for how long the Zagwe dynasty ruled: the more common tradition states that it was for 333 years, while a less common one gives the time as 133 years. The Italian scholar Carlo Conti Rossini accepted the shorter period, and working back from the accepted date of 1270 for the end of the Zagwe dynasty, claims that this dynasty started around 1137. He supported this theory with the recorded exchange between Patriarch John V of Alexandria and an unnamed king of Ethiopia, who asked for a new abuna because the current one was too old; Conti Rossini argued that the actual reason was that the abuna refused to condone the coup which resulted in Mara Takla Haymanot gaining the throne.[2]